It's a hacked ROM, that's why on-line battling and trading is most likely not supported.
If it was, it would probably act as Emerald core which means you would be battling with Pokémon that were replaced by new ones.
That also answers your another question, if trading was possible and your friend e.g. traded you his Charmander, you would get Charmander's data which are represented by Chimchar.
In other words you would get a Chimchar.
Each Pokémon is represented by its data, you cannot have more than 386+25 Pokémon in one ROM (although there are guys who are working on extended Pokédex but for now, only 411 can be insterted)